Techniques for fluid sample separation are of wide applications, such as separation of cells, separation of fetal cells, cell separation for whole blood samples, and separation of endothelial colony forming cells (ECFC) contained in umbilical cord blood (UCB).
For example, detection and quantification of cancer cells or rare cells present in body fluids are regarded as a potential indicator for clinical diagnoses, prognostication, and biomedicine research. For example, circulating tumor cells (CTC) are rare in the blood of patients with metastatic cancer, and it is possible to monitor the response of CTC to adjuvant therapy. Such rear cells must be first separated from the body fluids, before detection and quantification of these rare cells can be made. For such a purpose, various cell techniques have been developed.
The cell separation techniques that are commonly used includes fluorescence activated cell separation (FACS), dielectrophoresis (DEP) cell separation, separation techniques that employ massively parallel microfabricated sieving devices, magnetically activated cell separation (MACS), and other techniques that uses optics and acoustics. Among these cell separation techniques, FACS and MACS are most often used.
Although it is often used, FACS is disadvantageous in respect of high cost, difficulty in disinfection, and consuming a great amount of sample in the operation thereof. Contrary to FACS, MACS is efficient to obtain a major quantity of target cells in a short period with a reduced consumption of sample. However, these cells must be transferred to a slide or an observation platform before they can be observed with a microscope. Such a process of transfer often leads to a great loss of cells.
Since MACS shows advantages in respect of high throughput, high performance, and simplified facility, it is often adopted in separation of fluid samples. Using immune cells to separate a desired component from a blood sample and the operation of immunofluorescence require multiple samples and manually-operated transfer, so that the result of detection is heavily dependent upon the skill of an operator, making it not fit for industrial use.